This invention relates in general to universal joints and in particular to an improved strap for retaining a bearing cup mounted on a universal joint cross to an end yoke and for preventing relative rotation therebetween during use.
Universal joints are well known devices which provide a driving connection between two members adapted to rotate about non-aligned axes of rotation. Universal joints of this type are widely used between rotatable drive shafts in vehicle drive train systems. Typically, such universal joints include a cross having a central body portion with four trunnions extending outwardly therefrom. The trunnions are oriented in a single plane and extend at right angles relative to one another. A bearing cup is mounted on the end of each of the trunnions. Needle bearings or similar friction reducing means are provided between each of the trunnions and its associated bearing cup to permit the bearing cup to rotate freely relative to the trunnion. One pair of opposed bearing cups is connected to a first end yoke secured to the first drive shaft, while the other pair of opposed bearing cups is connected to a second end yoke secured to the second drive shaft.
When the axes of rotation of the two drive shafts are not co-axially aligned during operation, the bearing cups rotate relative to the trunnions in an oscillating fashion so as to permit the driving connection. It is desirable that the bearing cups be fixed in position relative to the end yokes connected thereto such that no relative rotation occurs therebetween. Otherwise, wear will occur in the end yokes and in the outer surfaces of the bearing cups, causing premature failure of the universal joint.
Many structures are known for preventing relative rotation between the bearing cups and the end yokes. For example, it is known to secure a retainer strap to the arms of a half round end yoke so as to frictional engage the bearing cup and retain it within a recess formed in the end yoke. However, it has been found that such frictional engagement has not, of itself, been sufficient to prevent relative rotation between the end yoke and the bearing cup under all operating conditions. It is also known to provide a flange on the retainer strap which, when assembled, extends into engagement with a recess formed in the closed end surface of the bearing cup. Such a structure, while effective in preventing relative rotation between the bearing cup and the end yoke, requires the proper orientation of the retainer strap relative to the end yoke, and of the bearing cup relative to the retainer strap. This structure, as with other bearing cup retainer straps known in the art, thus requires additional labor to construct and install, increasing the cost of the universal joint assembly. Accordingly, it would be desirable to provide an improved universal joint assembly with a bearing cup retainer strap which is simple and inexpensive to construct and assemble.